Purpose:
To compare the optical coherence tomography (OCT) of the optic nerve from patients with multiple sclerosis (MS) and neuromyelitis optica (NMO).

Methods:
Patients with MS (n=5, 29.4 ± 2.88 years old) and NMO (n=10, 30.8 ± 8.27 years old) were tested with OCT. The following parameters were evaluated: average retinal nerve fiber layer (RNFL), nerve head volume, cup-disc area ratio, optic nerve head map of the superior (S), nasal (N), inferior (I) and temporal (T) regions. Both groups were compared to each other and to an age and gender-matched control group. Statistical analyses used: two-way ANOVA, Tukey's post hoc test, α=0.05.

Results:
MS and NMO patients had average RNFL lower than the control (p<0.01), while there were no statistical difference between MS group and NMO group. There were no statistical differences between nerve head volume and cup-disc area ratio among the groups. The analysis of the optic nerve head topography provided no significant difference between MS group and NMO group (p>0.05), but the MS group had lower values than the control group in the superior, inferior and temporal regions (p<0.001). NMO group also showed lower results than the controls at all optic nerve regions.

Conclusions:
The NMO and MS groups showed similar damage in the optic nerve. The values of nerve head volume and cup-disc area ratio were preserved in comparison to the control group. However, the values of average RNFL were reduced.